Looking for tigers? Follow your nose. Most people don’t get excited at the scent of urine. It’s pretty awful most of the time, let’s be honest. But in the right place at the right time… it can be a thrilling experience.

Before you become repulsed and stop reading, let me explain. When you’re a biologist working to conserve tigers, it can be pretty tricky to actually spot individuals in the wild. Their habitat is often dense forest, and they are solitary animals; they don’t have a herd to give away their game of hide and seek. They’re also sleek and fast--all told, perfect for remaining out of sight. Tiger conservationists often rely on motion-trigged camera traps (usually affixed to trees) to track tiger movements and understand populations. So if you’re in the field and trying to detect the presence of a tiger, a print in the sand, a scrape on a tree, a growl in the night or, yes, a whiff of their urine is the next best thing to actually seeking those tell-tale stripes slinking through the trees.

In May of 2016, I set out with a team from the Thailand’s Department of National Parks, Wildlife and Plant Conservation (DNP) and Freeland Foundation to establish the first estimate of tiger populations in an area of Thailand’s Eastern Forest Complex. Freeland Foundation had been placing cameras in the area for the past nine years, so we knew there were tigers in the area—just not how many. A small team of hardy DNP forest guards and Freeland began the process of deploying 176 cameras across the study area. Setting camera traps in the right spots takes more than just guesswork. A good camera site is one that already shows signs that it is part of a tiger’s home turf: tiger tracks, a “pinch point” in the landscape that animals might use as a pathway, or scrapes and scats… but best of all is a scent-marking area. Tigers regularly visit certain parts of their territory and mark them with urine, so setting a camera at one of these scent-marking areas means you are bound to get some tiger images.

One morning, we set out from camp early to deploy three pairs of cameras, the farthest one 8km away. We trudged through thick strands of rattan that tore my shirt to shreds and ripped at my skin (and we were on the easy route!). As we reached our destination, I suddenly hit a pungent wall of odour—the unmistakable musty smell of a tiger scent marking. The smell is not as unpleasant as you might think—imagine a cross-between wet tobacco, treacle and ammonia. We soon found fresh drops of liquid on the undersides of nearby leaves—we must have missed the tiger on the path by mere minutes. Never had wee smelt so sweet! We had hit the camera trap location jackpot.

The dense vegetation around us meant the culprit could be watching us while we snooped around its home. The hair on the back of my neck stood up at the prospect of coming face to face with a potentially hungry tiger. We carefully set a pair of cameras on either side of the trail to ensure that the next time the tiger passed by, photos would be snapped of its left and right flanks, allowing us to keep tabs on the individual by its unique fingerprint-like pattern of stripes. With enough data about individual tigers, we would eventually be able to estimate the population size.

Following our noses that day helped ensure that the cameras we set on this project produced the first ever scientific estimate of tigers for the area. Some of the images captured were of tiger cubs, evidence that this area is only the second known breeding population of the Indochinese subspecies in the world—a rare piece of good news for tiger conservation. We are continuing our work with the DNP and Freeland Foundation to strengthen the chance that these young tigers grow up safely and ultimately contribute to the long-term survival of the species in the region. By working together (and following our noses), we can ensure a future for wild tigers.